TPUT
Section: POSIX Programmer's Manual (P)
Updated: 2003
NAME
tput - change terminal characteristics
SYNOPSIS
tput [-T type] operand...
DESCRIPTION
The tput utility shall display terminal-dependent information.
The manner in which this information is retrieved is
unspecified. The information displayed shall clear the terminal screen,
initialize the user's terminal, or reset the user's
terminal, depending on the operand given. The exact consequences of
displaying this information are unspecified.
OPTIONS
The tput utility shall conform to the Base Definitions volume
of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following option shall be supported:
- -T type
-
Indicate the type of terminal. If this option is not supplied and
the TERM variable is unset or null, an unspecified
default terminal type shall be used. The setting of type shall
take precedence over the value in TERM .
OPERANDS
The following strings shall be supported as operands by the implementation
in the POSIX locale:
- clear
-
Display the clear-screen sequence.
- init
-
Display the sequence that initializes the user's terminal in an implementation-defined
manner.
- reset
-
Display the sequence that resets the user's terminal in an implementation-defined
manner.
If a terminal does not support any of the operations described by
these operands, this shall not be considered an error
condition.
STDIN
Not used.
INPUT FILES
None.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of
tput:
- LANG
-
Provide a default value for the internationalization variables that
are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables
for
the precedence of internationalization variables used to determine
the values of locale categories.)
- LC_ALL
-
If set to a non-empty string value, override the values of all the
other internationalization variables.
- LC_CTYPE
-
Determine the locale for the interpretation of sequences of bytes
of text data as characters (for example, single-byte as
opposed to multi-byte characters in arguments).
- LC_MESSAGES
-
Determine the locale that should be used to affect the format and
contents of diagnostic messages written to standard
error.
- NLSPATH
-
Determine the location of message catalogs for the processing of LC_MESSAGES
.
- TERM
-
Determine the terminal type. If this variable is unset or null, and
if the -T option is not specified, an unspecified
default terminal type shall be used.
ASYNCHRONOUS EVENTS
Default.
STDOUT
If standard output is a terminal device, it may be used for writing
the appropriate sequence to clear the screen or reset or
initialize the terminal. If standard output is not a terminal device,
undefined results occur.
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values shall be returned:
- 0
-
The requested string was written successfully.
- 1
-
Unspecified.
- 2
-
Usage error.
- 3
-
No information is available about the specified terminal type.
- 4
-
The specified operand is invalid.
- >4
-
An error occurred.
CONSEQUENCES OF ERRORS
If one of the operands is not available for the terminal, tput
continues processing the remaining operands.
The following sections are informative.
APPLICATION USAGE
The difference between resetting and initializing a terminal is left
unspecified, as they vary greatly based on hardware types.
In general, resetting is a more severe action.
Some terminals use control characters to perform the stated functions,
and on such terminals it might make sense to use
tput to store the initialization strings in a file or environment
variable for later use. However, because other terminals
might rely on system calls to do this work, the standard output cannot
be used in a portable manner, such as the following
non-portable constructs:
-
ClearVar=`tput clear`
tput reset | mailx -s "Wake Up" ddg
EXAMPLES
- 1.
-
Initialize the terminal according to the type of terminal in the environmental
variable TERM . This command can be
included in a .profile file.
-
tput init
- 2.
-
Reset a 450 terminal.
-
tput -T 450 reset
RATIONALE
The list of operands was reduced to a minimum for the following reasons:
- *
-
The only features chosen were those that were likely to be used by
human users interacting with a terminal.
- *
-
Specifying the full terminfo set was not considered desirable,
but the standard developers did not want to select among
operands.
- *
-
This volume of IEEE Std 1003.1-2001 does not attempt to provide
applications with sophisticated terminal handling
capabilities, as that falls outside of its assigned scope and intersects
with the responsibilities of other standards bodies.
The difference between resetting and initializing a terminal is left
unspecified as this varies greatly based on hardware types.
In general, resetting is a more severe action.
The exit status of 1 is historically reserved for finding out if a
Boolean operand is not set. Although the operands were
reduced to a minimum, the exit status of 1 should still be reserved
for the Boolean operands, for those sites that wish to support
them.
FUTURE DIRECTIONS
None.
SEE ALSO
stty , tabs
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- OPERANDS
-
- STDIN
-
- INPUT FILES
-
- ENVIRONMENT VARIABLES
-
- ASYNCHRONOUS EVENTS
-
- STDOUT
-
- STDERR
-
- OUTPUT FILES
-
- EXTENDED DESCRIPTION
-
- EXIT STATUS
-
- CONSEQUENCES OF ERRORS
-
- APPLICATION USAGE
-
- EXAMPLES
-
- RATIONALE
-
- FUTURE DIRECTIONS
-
- SEE ALSO
-
- COPYRIGHT
-
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